Nod1 signaling overcomes resistance of S. pneumoniae to opsonophagocytic killing

Airway infection by the Gram-positive pathogen Streptococcus pneumoniae (Sp) leads to recruitment of neutrophils but limited bacterial killing by these cells. Co-colonization by Sp and a Gram-negative species, Haemophilus influenzae (Hi), provides sufficient stimulus to induce neutrophil and complement-mediated clearance of Sp from the mucosal surface in a murine model. Products from Hi, but not Sp, also promote killing of Sp by ex vivo neutrophil-enriched peritoneal exudate cells. Here we identify the stimulus from Hi as its peptidoglycan. Enhancement of opsonophagocytic killing was facilitated by signaling through nucleotide-binding oligomerization domain-1 (Nod1), which is involved in recognition of γ-D-glutamyl-meso-diaminopimelic acid (meso-DAP) contained in cell walls of Hi but not Sp. Neutrophils from mice treated with Hi or compounds containing meso-DAP, including synthetic peptidoglycan fragments, showed increased Sp killing in a Nod1-dependent manner. Moreover, Nod1-/- mice showed reduced Hi-induced clearance of Sp during co-colonization. These observations offer insight into mechanisms of microbial competition and demonstrate the importance of Nod1 in neutrophil-mediated clearance of bacteria in vivo

Contribution of land use changes to near-surface air temperatures during recent summer extreme heat events in the Phoenix Metropolitan Area

The impact of 1973–2005 land use–land cover (LULC) changes on near-surface air temperatures during four recent summer extreme heat events (EHEs) are investigated for the arid Phoenix, Arizona, metropolitan area using the Weather Research and Forecasting Model (WRF) in conjunction with the Noah Urban Canopy Model. WRF simulations were carried out for each EHE using LULC for the years 1973, 1985, 1998, and 2005. Comparison of measured near-surface air temperatures and wind speeds for 18 surface stations in the region show a good agreement between observed and simulated data for all simulation periods. The results indicate consistent significant contributions of urban development and accompanying LULC changes to extreme temperatures for the four EHEs. Simulations suggest new urban developments caused an intensification and expansion of the area experiencing extreme temperatures but mainly influenced nighttime temperatures with an increase of up to 10 K. Nighttime temperatures in the existing urban core showed changes of up to 2 K with the ongoing LULC changes. Daytime temperatures were not significantly affected where urban development replaced desert land (increase by 1 K); however, maximum temperatures increased by 2–4 K when irrigated agricultural land was converted to suburban development. According to the model simulations, urban landscaping irrigation contributed to cooling by 0.5–1 K in maximum daytime as well as minimum nighttime 2-m air temperatures in most parts of the urban region. Furthermore, urban development led to a reduction of the already relatively weak nighttime winds and therefore a reduction in advection of cooler air into the city

Commensal Bacteroidetes protect against Klebsiella pneumoniae colonization and transmission through IL-36 signalling

The microbiota primes immune defences but the identity of specific commensal microorganisms that protect against infection is unclear. Conversely, how pathogens compete with the microbiota to establish their host niche is also poorly understood. In the present study, we investigate the antagonism between the microbiota and Klebsiella pneumoniae during colonization and transmission. We discover that maturation of the microbiota drives the development of distinct immune defence programmes in the upper airways and intestine to limit K. pneumoniae colonization within these niches. Immune protection in the intestine depends on the development of Bacteroidetes, interleukin (IL)-36 signalling and macrophages. This effect of Bacteroidetes requires the polysaccharide utilization locus of their conserved commensal colonization factor. Conversely, in the upper airways, Proteobacteria prime immunity through IL-17A, but K. pneumoniae overcomes these defences through encapsulation to effectively colonize this site. Ultimately, we find that host-to-host spread of K. pneumoniae occurs principally from its intestinal reservoir, and that commensal-colonization-factor-producing Bacteroidetes are sufficient to prevent transmission between hosts through IL-36. Thus, our study provides mechanistic insight into when, where and how commensal Bacteroidetes protect against K. pneumoniae colonization and contagion, providing insight into how these protective microorganisms could be harnessed to confer population-level protection against K. pneumoniae infection

A participatory methodology for large scale field trials in the UK

Farmer participation was essential in developing a uniquely useful set of wheat variety trials data on a wide range of organic farms over two years. Although the trials were successful, it became clear that some of the participating farmers felt there were some limitations in the process. These included a lack of ownership in the project and a concern for more researcher help. It was clear that a greater time in-vestment was needed at the start of the project to help with farmer understanding and ownership. De-spite the negative comments, farmers appreciated their involvement, particularly in contrasting their own views and information with that from the wider scene. Farmer participation is essential for systems-level research and this project helped to develop a small core of trained farmers and researchers

Quantifying the Origin and Distribution of Intracluster Light in a Fornax-like Cluster

Using a cosmological $N$-body simulation, we investigate the origin and distribution of stars in the intracluster light (ICL) of a Fornax-like cluster. In a dark matter only simulation we identify a halo which, at $z=0$, has $M_200 \simeq 4.1 \times 10^{13}M_{sun}$ and $r_{200} = 700kpc$, and replace infalling subhalos with models that include spheroid and disc components. As they fall into the cluster, the stars in some of these galaxies are stripped from their hosts, and form the ICL. We consider the separate contributions to the ICL from stars which originate in the haloes and the discs of the galaxies. We find that disc ICL stars are more centrally concentrated than halo ICL stars. The majority of the disc ICL stars are associated with one initially disc-dominated galaxy that falls to the centre of the cluster and is heavily disrupted, producing part of the cD galaxy. At radial distances greater than 200kpc, well beyond the stellar envelope of the cD galaxy, stars formerly from the stellar haloes of galaxies dominate the ICL. Therefore at large distances, the ICL population is dominated by older stars.Comment: Paper published as MNRAS , 2017, 467, 4501 This version corrects a small typo in the authors fiel

A Class of Eccentric Binaries with Dynamic Tidal Distortions Discovered with Kepler

We have discovered a class of eccentric binary systems within the Kepler data archive that have dynamic tidal distortions and tidally-induced pulsations. Each has a uniquely shaped light curve that is characterized by periodic brightening or variability at time scales of 4-20 days, frequently accompanied by shorter period oscillations. We can explain the dominant features of the entire class with orbitally-varying tidal forces that occur in close, eccentric binary systems. The large variety of light curve shapes arises from viewing systems at different angles. This hypothesis is supported by spectroscopic radial velocity measurements for five systems, each showing evidence of being in an eccentric binary system. Prior to the discovery of these 17 new systems, only four stars, where KOI-54 is the best example, were known to have evidence of these dynamic tides and tidally-induced oscillations. We perform preliminary fits to the light curves and radial velocity data, present the overall properties of this class and discuss the work required to accurately model these systems.Comment: 13 pages, submitted to Ap

Elm Farm Organic Research Centre Bulletin 83 April 2006

Regular bulleting with technical updates from Organic Advisory Service Issue contains: Testing for Tolerance - a pragmatic view GM Debate Vaccination nation - to jab or not to jab Future shape of OCIS Evolutionary wheat makes the grade? NIAB tracks health of organic cereal seed Stopping erosion of soil quality - the organic way Care needed to halt butterfly collapse Aspects of poultry behaviour: How free range is free range? On choosing an organic wheat A local education challenge New Wakelyns Science Building Organic vegetable market growt

Move of a large but delicate apparatus on a trailer with air-ride suspension

When valuable delicate goods are shipped by truck, attention must be paid to vibrations that may cause damage. We present a case study of moving an extremely delicate 6230-kg superconducting magnet, immersed in liquid nitrogen, from Livermore, CA to Seattle, WA showing the steps of fatigue analysis of the load, a test move, and acceleration monitoring of the final move to ensure a successful damage-free transport

Longitudinal Ion Acceleration from High-Intensity Laser Interactions with Underdense Plasma

Longitudinal ion acceleration from high-intensity (I ~ 10^20 Wcm^-2) laser interactions with helium gas jet targets (n_e ~ 0.04 n_c) have been observed. The ion beam has a maximum energy for He^2+ of approximately 40 MeV and was directional along the laser propagation path, with the highest energy ions being collimated to a cone of less than 10 degrees. 2D particle-in-cell simulations have been used to investigate the acceleration mechanism. The time varying magnetic field associated with the fast electron current provides a contribution to the accelerating electric field as well as providing a collimating field for the ions. A strong correlation between the plasma density and the ion acceleration was found. A short plasma scale-length at the vacuum interface was observed to be beneficial for the maximum ion energies, but the collimation appears to be improved with longer scale-lengths due to enhanced magnetic fields in the ramp acceleration region.Comment: 18 pages, 6 figure